Receiving coil device, receiving coil unit, and manufacturing method

Abstract

Provided is a receiving coil device that receives a magnetic resonance signal generated from a subject, the receiving coil device comprising: a first loop coil element corresponding to a first channel; and a second loop coil element corresponding to a second channel. The first loop coil element is disposed at the outer side of a row of teeth in the oral cavity of the subject such that the loop surface of the first loop coil element faces a site to be examined, and the second loop coil element is disposed at the inner side of the row of teeth in the oral cavity of the subject such that the loop surface of second loop coil element faces the site to be examined.

Description

Receive coil device, receive coil unit, and manufacturing method

[0001] The present invention relates to magnetic resonance imaging (MRI) technology.

[0002] In magnetic resonance imaging devices, a technique is known in which a receiver coil specialized for a specific part of a subject is used to obtain an image of that part. Patent Document 1 and Non-Patent Document 1 disclose receiver coils that are inserted into the oral cavity. Non-Patent Document 1 discloses a configuration in which a saddle-shaped, one-channel receiver coil is attached to the teeth.

[0003] Patent No. 4138563

[0004] Ute Ludwig, et al., Dental MRI using wireless intraoral coils, [online], 2016, [Retrieved April 2, 2024], Internet <URL https: / / www.nature.com / articles / srep23301>

[0005] The three-dimensional anatomical morphology of dental nerves has become increasingly diverse, and three-dimensional, qualitative nerve diagnosis will become increasingly important in the future. The treatment of dental caries involves a major decision on whether or not to remove the dental nerve. Avoiding the nerve can significantly reduce the burden on patients. Even if a cavity has progressed to the dental nerve, new treatment strategies can be applied that remove only the inflamed or pus-filled areas, leaving the nerves of the crown and root intact. During such treatments, MRI technology can provide images of the patient's treatment site, which is extremely useful for planning subsequent treatment plans. Furthermore, in recent years, it has become recognized that dental health is closely related to various systemic illnesses and dementia, leading to dental diagnosis before general anesthesia surgery and cancer radiation therapy. MRI technology can also be used in pre-surgical dental diagnosis.

[0006] To achieve precise diagnosis, it is desirable to obtain high-resolution magnetic resonance images. However, placing a receiving coil in the oral cavity of a patient for a long period of time and requiring the patient to remain still in the oral cavity can cause discomfort to the patient. Conventional technologies have room for improvement in terms of obtaining high-quality images in a shorter time.

[0007] An object of the present invention is to provide a technique that enables high-quality magnetic resonance images to be obtained in a shorter time.

[0008] According to the present invention, there is provided a receive coil device (1) for receiving magnetic resonance signals generated from a subject (200), comprising: a first loop coil element (C1) corresponding to a first channel (CH1); and a second loop coil element (C2) corresponding to a second channel (CH2), wherein the first loop coil element (C1) is arranged outside the dentition (202) in the oral cavity of the subject (200) so that its loop surface (CF) faces the area to be examined, and the second loop coil element (C2) is arranged inside the dentition (202) in the oral cavity of the subject (200) so that its loop surface (CF) faces the area to be examined.

[0009] According to the present invention, it is possible to provide a technique that allows high-quality magnetic resonance images to be obtained in a shorter time.

[0010] 7 is a schematic diagram of a magnetic resonance imaging apparatus to which the present invention can be applied. An exploded perspective view of a receive coil device according to one embodiment of the present invention. An explanatory diagram of the internal structure of a receive coil unit according to one embodiment of the present invention. An explanatory diagram of the internal structure of the receive coil unit of Figure 3. Circuit diagrams of two receive coil units. A cross-sectional view of a support member taken along line A-A in Figure 2. A diagram showing an example of how the receive coil device of Figure 2 is worn on a subject. A view of the wearing example of Figure 7 from the upper jaw side. A view of the wearing example of Figure 7 from the right cheek side. A cross-sectional view taken along line B-B in Figure 9. A diagram showing an example of a manufacturing method of a support member. A cross-sectional view showing another embodiment. A view showing another embodiment. A view showing another embodiment.

[0011] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention as claimed, and not all combinations of features described in the embodiments are necessarily essential to the invention. Two or more of the features described in the embodiments may be arbitrarily combined. Furthermore, the same reference numerals are used for the same or similar components, and redundant explanations will be omitted.

[0012] <First Embodiment> <Outline of Magnetic Resonance Imaging Apparatus> Fig. 1 is a schematic diagram of a magnetic resonance imaging apparatus (MRI apparatus) 100 to which a receive coil device of the present invention can be applied. The MRI apparatus 100 includes a movable table 101 on which a subject 200 lies. The movable table 101 moves the subject 200 in and out of a cavity 106 of a cylindrical magnet section 102. The magnet section 102 is provided with a superconducting coil 103 that generates a static magnetic field in the cavity 106, a gradient coil 104 that generates a magnetic field gradient in the cavity 106, and a transmit coil 105 that transmits RF signals.

[0013] The receive coil device 1 is placed in the oral cavity of the subject 200 and includes an RF coil for receiving magnetic resonance signals generated from the subject 200. In this embodiment, an existing MRI device is used as the MRI device 100, and by adding the receive coil device 1, it is possible to obtain multi-plane tomographic images of the oral cavity of the subject 200.

[0014] The receiving coil device 1 is equipped with a multi-channel coil with independent channels. The receiving coil device 1 of this embodiment is equipped with loop coil elements C1 to C4 corresponding to four channels (CH1 to CH4). The loop coil elements C1 to C4 may be referred to as elements C1 to C4.

[0015] The magnetic resonance signals received by each of the elements C1 to C4 are processed by a signal processing circuit 120 and input to the control device 110. The signal processing circuit 120 includes an amplifier 121, a filter 122, a detection circuit 123, and an A / D converter 124 for each of the elements C1 to C4.

[0016] The control device 110 is an electronic circuit equipped with a processor, a storage device storing a program executed by the processor, and an interface with peripheral devices. The control device 110 is connected to an input device 111 such as a pointing device, keyboard, or touch panel that can be operated by a user, and a display device 112. The control device 110 controls the MRI apparatus 100 in accordance with instructions from the user, and reconstructs tomographic images of the teeth and periodontal tissues of the subject 200 from the magnetic resonance signals received by the receive coil device 1, and displays the reconstructed images on the display device 112.

[0017] The control device 110 may transfer the tomographic image data to a predetermined destination via a communication line. The destination may be, for example, another department (such as an operating room or a department) in the hospital where the MRI device 100 is installed, or another hospital or research facility. Instead of transmitting the tomographic image data via a communication line, the control device 110 may store the tomographic image data on a storage medium such as a CD-R and send the storage medium. Personal information may be anonymized when the data is stored.

[0018] <Receiver coil device> Fig. 2 is an exploded perspective view of a receiver coil device 1 according to one embodiment of the present invention. The receiver coil device 1 includes receiver coil units 2A and 2B and a support member 3. The receiver coil unit 2A includes a head unit 10 having elements C1 and C3, and a cable 20 extending from the head unit 10. The receiver coil unit 2B includes a head unit 10 having elements C2 and C4, and a cable 20 extending from the head unit 10. The support member 3 is attached to a part of the dentition of the subject 200, and detachably supports each head unit 10. First, the receiver coil units 2A and 2B will be described.

[0019] <Receiver coil unit> The receiver coil units 2A and 2B have the same structure. Here, the structure of the receiver coil unit 2A will be described in detail with reference to Figs. 3 and 4 in addition to Fig. 2. Figs. 3 and 4 are explanatory diagrams of the internal structure of the receiver coil unit 2A. In Figs. 2 to 4, arrows X, Y, and Z indicate three mutually orthogonal directions, and are a coordinate system set up for the sake of convenience in order to explain the structure of the receiver coil unit 2A, etc.

[0020] The head unit 10 has an outer shape that allows it to be placed on the side of the dentition of the upper or lower jaw of the subject 200 (between the dentition and the cheek, between the dentition and the lip, or between the dentition and the tongue), and in this embodiment, has an overall plate-like outer shape. In other words, the outer shape of the head unit 10 can be described as a pad-like, tablet-like, or thin shape.

[0021] The head unit 10 has two regions in the Z direction that differ in width (thickness) in the Y direction, one of which is a coil accommodating section 10a that is relatively thin, and the other is a circuit accommodating section 10b that is relatively thick. Elements C1 and C3 are arranged from the coil accommodating section 10a to the circuit accommodating section 10b, and electronic components related to elements C1 and C3 (capacitor 13, adjustment circuit 14, signal line SL, etc.) are arranged in the circuit accommodating section 10b.

[0022] The thickness Ty1 of the coil accommodating portion 10a is, for example, within a range of 1.5 to 4.5 mm, or, in a narrower range, within a range of 2.5 to 3.5 mm, with a specific example being 3.0 mm. By setting the thickness Ty1 within this range, the foreign body sensation felt by the subject 200 can be reduced even when the coil accommodating portion 10a is positioned deep on the side of the dentition. The thickness Ty2 of the circuit accommodating portion 10b is, for example, within a range of 3.0 to 7.0 mm, or, in a narrower range, within a range of 4.0 to 6.0 mm, with a specific example being 5.0 mm.

[0023] The head unit 10 has a contact surface SF1 that comes into contact with the part of the subject 200 to be examined, and an opposite surface SF2 on the opposite side. The contact surface SF1 is a flat surface (X-Z plane). By making the contact surface SF1 a flat surface, it is possible to improve the fit to the side of the dentition of the subject 200. The opposite surface SF2 has a step at the boundary between the coil accommodating portion 10a and the circuit accommodating portion 10b. Of the opposite surface SF2, the coil accommodating portion 10a and the circuit accommodating portion 10b are both flat surfaces (X-Z plane), and the step is in the Y direction.

[0024] An engagement portion 16 that engages with the support member 3 is formed on the opposite surface SF2. Engagement of the engagement portion 16 with the support member 3 allows the head unit 10 to be more firmly supported on the support member 3. The engagement portion 16 in this embodiment has the form of a protrusion that protrudes in the Y direction from the opposite surface SF2, and has a quadrangular pyramid shape or a wedge shape with a small cross-sectional area at the base and a large cross-sectional area at the tip. The engagement portion 16 also has the function of positioning the head unit 10 in the X and Z directions relative to the support member 3. The engagement portion 16 also has a rotation prevention function that regulates rotation of the head unit 10 around the Y axis relative to the support member 3.

[0025] The head unit 10 of this embodiment has a rectangular shape with its longer side in the X direction and its shorter side in the Z direction. The head unit 10 may also have a circular shape. However, a rectangular shape makes it easier to ensure a wider examination area in both the dentition direction and the depth direction when the head unit 10 is placed on the side of the dentition.

[0026] The width Wx of the head unit 10 in the X direction and the width Wz of the head unit 10 in the Z direction have a relationship of Wx > Wz. The width Wx is, for example, within a range of 20.0 mm to 40.0 mm, or a narrower range of 25.0 mm to 35.0 mm, with a specific example being 30.0 mm. The width Wz is, for example, within a range of 15.0 mm to 35.0 mm, or a narrower range of 20.0 mm to 30.0 mm, with a specific example being 25.7 mm.

[0027] The head unit 10 of this embodiment has a rounded rectangular outer shape, with four rounded corners 10c and 10d. When the head unit 10 is placed on the side of the subject's dentition, the foreign body sensation felt by the subject 200 can be reduced. The corner 10c on the coil accommodating portion 10a side has a larger radius of curvature than the corner 10d on the circuit accommodating portion 10b side. When the coil accommodating portion 10a is placed deep on the side of the dentition, the corner 10c with a larger radius of curvature comes into contact with the subject 200, further reducing the foreign body sensation felt by the subject 200. The radius of the corner 10c is, for example, within a range of 2.0 mm to 6.0 mm. A narrower range of width is, for example, within a range of 3.0 mm to 5.0 mm, with a specific width being, for example, 4.0 mm. Instead of being rounded, the corners 10c and 10d may be chamfered.

[0028] The receiving coil unit 2A includes elements C1 and C3. Elements C1 and C3 have a single-turn loop shape, and in this embodiment, are rectangular with the short side in the X direction and the long side in the Z direction. The outer shape of elements C1 and C3 may be circular. However, a rectangular shape makes it easier to ensure a wider receiving area in both the tooth row direction and the depth direction when the head unit 10 is placed on the side of the tooth row.

[0029] The width CWx of element C1 in the X direction and the width CWz of element C1 in the Z direction satisfy the relationship CWx<CWz. The width CWx is, for example, within a range of 9.0 mm to 15.0 mm, with a narrower range being 11.0 to 13.0 mm, and a specific example being 12.0 mm. The width CWz is, for example, within a range of 12.0 mm to 22.0 mm, with a narrower range being 14.0 to 18.0 mm, and a specific example being 15.0 mm or 17.0 mm. These dimensions allow at least one tooth and its surrounding periodontal tissue to be included in the detection range. Element C3 has similar dimensions, and elements C1 and C3 together allow approximately three teeth and their surrounding periodontal tissue to be included in the detection range.

[0030] The elements C1 and C3 in this embodiment have the same rounded rectangle shape. Because the elements C1 and C3 are made of metal wire, the subject 200 may feel a hard texture when the head unit 10 is placed on the side of the subject's dentition. The rounded corners of the elements C1 and C3 can reduce the foreign body sensation felt by the subject 200 when the head unit 10 is placed on the side of the subject's dentition.

[0031] Elements C1 and C3 are arranged at approximately the same position in the Z direction, but at positions offset in the X direction. By arranging elements C1 and C3 at positions offset in the X direction, it is easy to ensure a wider inspection area. In this embodiment, elements C1 and C3 are arranged to have an area P where they overlap in the X direction. Interference between elements C1 and C3 can be suppressed. The width of area P in the X direction is, for example, within a range of 1.5 mm to 3.5 mm, and an example of a narrower range of width is within a range of 2.0 to 3.0 mm, with a specific example being 2.5 mm.

[0032] The loop plane CF of each of the elements C1 and C3 is parallel to the contact plane SF1 (XZ plane). The axial direction AX of each of the loops of the elements C1 and C3 is the normal direction to the loop plane CF, which is the Y direction.

[0033] The receiving coil unit 2A has a covering portion 15. The covering portion 15 is integrally provided with a head covering portion 15a that covers the entire head unit 10 and a cable covering portion 15b that covers a portion of the cable 20. The head covering portion 15a covers each component of the head unit 10 (elements C1 and C3, and electronic components (12-14, SL)), and forms the outer shape of the head unit 10 including the engagement portion 16. The cable covering portion 15b covers the cable 20 within a predetermined range from the head unit 10 side. The cable covering portion 15b is designed to cover at least the portion of the cable 20 that enters the oral cavity of the subject 200.

[0034] The covering 15 is made of, for example, an elastomer, more specifically, biocompatible silicone (medical silicone). Using biocompatible silicone for the covering 15 can reduce the foreign body sensation felt by the subject 200 when the head unit 10 and other components are placed in the subject's oral cavity. Furthermore, the adhesion between the contact surface SF1 of the head unit 10 and the examination target area in the subject's oral cavity is improved, allowing the elements C1 and C3 to be positioned closer to the examination target area. This improves the image quality of the magnetic resonance image. Furthermore, due to the physical properties of silicone, the covering 15 may appear in the magnetic resonance image depending on the location of the tomography. However, the location of this appearance can be used as a factor in determining whether the elements C1 and C3 are placed in the appropriate location. Furthermore, the receiving coil unit 2A can be reused by disinfecting it, improving economy.

[0035] The configuration of the electric circuits of the receiver coil units 2A and 2B will be described with reference to Figures 3 to 5. Figure 5 is a circuit diagram of the receiver coil units 2A and 2B. Each of the elements C1 to C4 is formed by a conductor 11 wound once in a loop shape, with multiple capacitors 12 inserted (connected in series) along the way to adjust the resonant frequency. Each end of the element C1 is connected to a capacitor 13, and the element C1 and the capacitor 13 form a resonant circuit.

[0036] The voltage between the terminals of the capacitor 13 is output to a pair of signal lines SL via an adjustment circuit 14. The adjustment circuit 14 includes a coil 14a directly connected to one of the pair of signal lines SL and a diode 14b connected between the pair of signal lines SL, and is a circuit for preventing magnetic coupling with the transmission coil 105.

[0037] The cable 20 is composed of two coaxial cables. The cable 20 of the receiving coil unit 2A includes a coaxial cable of a pair of signal lines SL (core wire and shield wire) corresponding to element C1, and a coaxial cable of a pair of signal lines SL (core wire and shield wire) corresponding to element C3. Similarly, the cable 20 of the receiving coil unit 2B includes a coaxial cable of a pair of signal lines SL (core wire and shield wire) corresponding to element C2, and a coaxial cable of a pair of signal lines SL (core wire and shield wire) corresponding to element C4. The two cables 20 are connected to a connector 4. The connector 4 is connected to a control device 110.

[0038] <Support Member> The support member 3 will be described with reference to Figures 2 and 6. Figure 6 is a cross-sectional view taken along line A-A in Figure 2, and is a cross-sectional view of the Z-Y plane at the center in the X direction of the support member 3. The support member 3 is a member that straddles the row of teeth and supports two head units 10 on either side of the row of teeth.

[0039] The support member 3 includes a pair of coil support portions 31 spaced apart in the Y direction, and a base portion 32 that is provided between the pair of coil support portions 31 and is sandwiched between the upper and lower teeth of the subject 200. Each coil support portion 31 has an abutment surface 31a that abuts against the opposite surface of the head unit 10, and is a plate-like portion that extends in the Z direction from the base portion 32. The abutment surfaces 31a of the pair of coil support portions 31 face each other. The two head units 10 and the teeth of the subject 200 are sandwiched between the abutment surfaces 31a of the pair of coil support portions 31.

[0040] A slot 37 is formed between the coil support portion 31 and the base portion 32. A part of the head unit 10 is inserted into and held in the slot 37. An engagement portion 36 that engages with an engagement portion of the head unit 10 is formed on the contact surface 31a. The engagement portion 36 is a recess with the same shape as the engagement portion 16, and has a quadrangular pyramid shape or a wedge shape with a large cross-sectional area on the bottom side and a small cross-sectional area on the open end side.

[0041] The base portion 32 includes a bridge portion 33 bridged between the pair of coil support portions 31, a tooth impression portion 34 formed on one surface in the Z direction of the bridge portion 33, and a tooth impression portion 35 formed on the other surface. The tooth impression portions 34 and 35 have an impression of the upper or lower jaw of the subject 200 formed therein.

[0042] The material of the support member 3 is, for example, an elastomer, and more specifically, for example, biocompatible silicone (medical silicone). The support member 3 may be formed entirely of the same material, or may be formed of materials with different properties. In this embodiment, the pair of coil support portions 31 and the bridge portion 33 are formed of the same biocompatible silicone, and the dental impression portions 34 and 35 are formed of biocompatible silicone with softer properties than the pair of coil support portions 31 and the bridge portion 33. By selecting such materials, the pair of coil support portions 31 and the bridge portion 33 that support the head unit 10 can be made more rigid, and the dental impression portions 34 and 35 that come into contact with the subject 200 can reduce the foreign body sensation felt by the subject 200. When biocompatible silicone is used as the material of the covering portion 15, biocompatible silicone with the same properties as the dental impression portions 34 and 35 may be used.

[0043] <Wearing Example> An example of how the receive coil device 1 is worn on the subject 200 will be described. FIG. 7 shows the mouth area of ​​the subject 200, illustrating an example of how the receive coil device 1 is worn. In the illustrated example, a portion of the right lower jaw dentition 202 and the surrounding periodontal tissue are the areas to be examined. For this reason, the receive coil device 1 is placed in the oral cavity 201 of the subject 200, between the right lower jaw dentition 202 and the upper jaw dentition 203. To stabilize the shape of the subject's 200's mouth, a mouthpiece 5 having a thickness approximately the same as the base portion 32 of the support member 3 is placed between the left lower jaw dentition 202 and the upper jaw dentition 203. The cable 20 is routed from inside the oral cavity 201 to the outside, and the portion that comes into contact with the subject 200 is covered by a covering portion 15b.

[0044] Please refer to Figures 8 to 10. Figure 8 is a diagram of the arrangement of the receive coil device 1 in Figure 7 viewed from the upper jaw side of the subject 200, with part of the support member 3 shown in phantom lines. Figure 9 is a diagram of the arrangement of the receive coil device 1 in Figure 7 viewed from the right cheek side of the subject 200, with part of the support member 3 shown in a see-through state. Figure 10 is a cross-sectional view taken along line B-B in Figure 9. In the illustrated example, part of the dentition 202 on the right mandible (the three teeth at the back) and the surrounding periodontal tissue are the detection target areas, and it is assumed that multi-plane tomographic images will be obtained from the tooth crowns to the tooth roots and surrounding gums.

[0045] When mounting the receiver coil device 1, first, the head units 10 of the receiver coil units 2A and 2B are mounted on the support member 3. The head units 10 are inserted into the slots 37 and mounted on the support member 3. When mounting, the engaging portions 16 are fitted into the engaging portions 36, so that the head units 10 are more firmly supported on the coil support portion 31. The circuit accommodating portion 10b of the head unit 10 is entirely covered by the coil support portion 31, but the coil accommodating portion 10a is entirely exposed. This makes it easier for the coil accommodating portion 10a to come into close contact with the area to be examined, and as a result, the elements C1 to C4 are closer to the area to be examined, resulting in a clearer image being obtained.

[0046] Next, the support member 3 supporting the two head units 10 is attached to a portion of the mandibular dentition 202. In the illustrated example, the head unit 10 of the receiver coil unit 2A is placed on the outer side of the dentition, and the head unit 10 of the receiver coil unit 2B is placed on the inner side of the dentition. Regarding the relationship between the XYZ coordinate system used in Figures 2 to 4 and the dentition 202, the receiver coil device 1 is placed so that the X direction is aligned with the dentition direction D1 of the dentition 202 in the examination area, and so that the Z direction is aligned with the up-down direction D2 of the teeth.

[0047] The tip of the coil housing 10a of each head unit 10 is inserted deep into the side of the dentition 202 (the valley between the cheek and gum, the valley between the gum and lip, and the valley between the tongue and gum). This allows the detection range to extend deep into the dentition. Meanwhile, the coil housing 10a is thin, the corners 10c are rounded, and the covering 15 is made of elastomer (particularly biocompatible silicone), which reduces the foreign body sensation felt by the subject 200.

[0048] Because the material of the support member 3 and the covering portion 15 is elastomer (especially biocompatible silicone), the support member 3 and the head unit 10 are able to undergo a certain degree of elastic deformation, allowing them to fit the area to be examined. As shown in Figure 10, the two head units 10 are attached at a slight angle to match the shape of the dentition and gums.

[0049] The contact surface SF1 of each head unit 10 faces the inspection target portion and is in contact with it. Therefore, the loop surface CF of each element C1 to C4 faces the inspection target portion, and its axial direction AX is oriented in a direction intersecting the tooth row direction D1. Elements C1 and C3 are arranged on the outside of the tooth row 202 with a shift in the tooth row direction D1, particularly with a partial overlap. Similarly, elements C2 and C4 are arranged on the inside of the tooth row 202 with a shift in the tooth row direction D1, particularly with a partial overlap.

[0050] The opposite surface SF2 of each head unit 10 is located on the opposite side (cheek side or tongue side) of the area to be examined. Because there is a relatively large amount of space on the opposite side, the presence of the circuit accommodating portion 10b, the engaging portion 16, and the coil supporting portion 31 can minimize the discomfort felt by the subject 200.

[0051] The base portion 32 of the support member 3 is sandwiched between the teeth of the upper jaw dentition 203 and the teeth of the lower jaw dentition 202. When the subject 200 loosely bites down on the base portion 32 with their upper and lower teeth, the shape of the subject's 200 mouth is stabilized and the positions of the elements C1 to C4 can be prevented from shifting during reception of magnetic resonance signals. Because the base portion 32 does not include the elements C1 to C4 or related circuit components, even if the subject 200 bites down on the base portion 32 relatively strongly, it does not adversely affect reception of magnetic resonance signals or damage the elements C1 to C4. Because the base portion 32 has tooth-shaped portions 34 and 35 formed thereon, the base portion 32 fits snugly against the upper and lower teeth of the subject 200, providing a sense of security to the subject 200 and preventing the positions of the elements C1 to C4 from shifting during reception of magnetic resonance signals.

[0052] As described above, the receive coil device 1 is attached to the subject 200, and an examination is performed using the MRI apparatus 100. The receive coil device 1 of this embodiment is equipped with a multi-channel coil, so that a high-quality magnetic resonance image can be obtained for the examination target area in a shorter time. Completing the examination in a shorter time can reduce the burden on the subject 200. Obtaining a high-quality magnetic resonance image can improve the accuracy and quality of image diagnosis.

[0053] The receive coil device 1 of this embodiment not only includes a multi-channel coil, but also employs a structure in which the elements C1 to C4 are distributed on the outside and inside of the dentition 202. This allows the multiple elements C1 to C4 to be efficiently arranged in the narrow oral cavity. Because the elements C1 to C4 are not located between the upper and lower teeth, the elements C1 to C4 are not affected even if the subject 200 moves their upper or lower jaws.

[0054] While miniaturizing the loop area of ​​each element C1 to C4 increases sensitivity, it may shorten the detection range in the axial direction AX. By arranging elements C1 to C4 on the outside and inside of tooth row 202 as in this embodiment, at least half of the detection range in the tooth width direction intersecting with tooth row direction D1 can be covered by elements C1 and C3, and at least the remaining half can be covered by elements C2 and C4, thereby achieving a wide detection range with high sensitivity.

[0055] Because the support member 3 and each head unit 10 are detachable, the support member 3 can be individually manufactured for each subject 200, while the receiving coil units 2A and 2B can be sterilized and reused. This reduces the cost of using the coil receiving device 1, and lowers the cost of treatment.

[0056] <Method of Manufacturing Support Member> An example of a method of manufacturing the support member 3 will be described with reference to Fig. 11. Fig. 11 is an explanatory diagram showing an example of the manufacturing procedure for the support member 3. In step S1, a dental impression 5a of the upper jaw and a dental impression 5b of the lower jaw of the subject 200 are made. The dental impressions 5a and 5b may be plaster models that are generally made in dental treatment, or may be made using a 3D printer.

[0057] Next, in step S2, a primary molded product 40 is created. The primary molded product 40 is created using the tooth dies 5a and 5b and the head units 10 of the receiver coil units 2A and 2B so as to have a shape suitable for the area to be inspected. The head units 10 may be dummy products having the same external shape as the actual head units 10.

[0058] The primary molded product 40 is a component of the support member 3, which is the final product, excluding the tooth impression portions 34 and 35. The primary molded product 40 can be made by hand by a dentist from uncured elastomer (e.g., biocompatible silicone), for example. Since the primary molded product 40 is composed of a pair of coil support portions 31 and a bridge portion 33, multiple types of coil support portions 31 and bridge portions 33 of different sizes may be prepared, and one of the coil support portions 31 and bridge portion 33 may be selected according to the size of the oral cavity 201 of the subject 200 and joined together to make the primary molded product.

[0059] Next, in step S3, uncured elastomer (for example, biocompatible silicone) 41 is attached to the top and bottom of the bridge portion 33 of the primary molded product 40. Subsequently, in step S4, a dental impression of the subject 200 is formed on the top and bottom elastomers 41, and the elastomers 41 are cured. The dental impression of the elastomers 41 may be formed using the dental impressions 5a and 5b created in step S1, or may be formed by having the subject 200 actually bite the primary molded product 40.

[0060] This completes the support member 3. A support member 3 optimized for each individual subject 200 can be manufactured.

[0061] Second Embodiment In the first embodiment, the right rear portion of the mandibular dentition 202 is exemplified as the portion to be examined, but the portion to be examined is not limited to this, and front teeth or a part of the maxillary dentition 203 can also be selected as appropriate. In the first embodiment, a support member 3 is exemplified that is intended for use in examining the area around the mandibular dentition. For this reason, a tooth impression of the maxillary dentition is formed in the tooth impression portion 34, and a tooth impression of the mandibular dentition is formed in the tooth impression portion 35. When the support member 3 is used for examining the area around the maxillary dentition, a tooth impression of the mandibular dentition is formed in the tooth impression portion 34, and a tooth impression of the maxillary dentition is formed in the tooth impression portion 35.

[0062] In the first embodiment, the receiver coil device 1 is attached to the subject 200 so that the X direction of the head unit 10 is aligned with the tooth row direction D1, but the support member 3 may be configured so that the X direction of the head unit 10 is aligned with the up-down direction D2, in which case it is possible to use a part of the lower jaw tooth row 202 and a part of the upper jaw tooth row 203 as the examination target areas. It is also possible to use long teeth such as upper jaw canines or areas with a large curvature of the tooth row as the examination target areas.

[0063] <Third Embodiment> In the first embodiment, the head unit 10 is configured to be detachable from the support member 3, but the support member 3 may include a portion corresponding to the head unit 10, and the elements C1 to C4 may be configured to be non-detachable from the support member 3. Fig. 12 is a cross-sectional view showing one such example, and corresponds to the cross-sectional view of Fig. 10.

[0064] The receive coil device 1A in Fig. 12 is assumed to be created as a dedicated product for each individual subject 200. In the receive coil device 1A, a support member 3A has a pair of coil support portions 31' and a base portion 32' between the pair of coil support portions 31'. The coil support portion 31' is integrally provided with a portion 10' corresponding to the head unit 10 of the first embodiment, and elements C1 to C4 are built into the pair of coil support portions 31'.

[0065] Fourth Embodiment In the first and third embodiments, the elements C1 to C4 are single-turn coils, but they may be multiple-turn coils.

[0066] Furthermore, although the example in which the receiving coil device 1 includes a four-channel multi-channel coil has been exemplified, it may also include a two-channel multi-channel coil, a three-channel multi-channel coil, or a five-channel or more multi-channel coil. When the receiving coil device 1 is configured to include a two-channel multi-channel coil, one loop coil element can be arranged on the inside and one on the outside of the dentition. When the receiving coil device 1 is configured to include a three-channel multi-channel coil, two loop coil elements can be arranged on the inside of the dentition and one loop coil element on the outside, or one loop coil element can be arranged on the inside of the dentition and two loop coil elements on the outside.

[0067] Fifth Embodiment The support member 3 of the first embodiment and the support member 3A of the third embodiment both have the tooth-shaped portions 34 and 35, but it is also possible to employ a configuration that does not have both or either of the tooth-shaped portions 34 and 35. In this case, the base portion 32 is formed only by the bridge portion 33, and the subject 200 bites the bridge portion 33.

[0068] In the first embodiment, one support member 3 is configured to support each head unit 10 of two receiver coil units 2A and 2B, but a configuration may be adopted in which each head unit of three or more receiver coil units is supported. Fig. 13 is a diagram showing an example of such a configuration, and is a diagram showing a receiver coil device 1B of this embodiment with the same line of sight as in Fig. 8.

[0069] The receiver coil device 1B includes a support member 3B that supports the head units 10 of the two receiver coil units 2A and the head units 10 of the two receiver coil units 2B. The support member 3B is formed into a C-shape overall along the curved shape of the dentition 202, and supports the four receiver coil units 2A and 2B from the right back teeth to the front teeth of the lower jaw. With this configuration, it is possible to perform an examination over a wider range in a single examination.

[0070] Seventh Embodiment The bridge portion 33 and the coil support portion 31 may have a shape further suited to an individual subject. Fig. 14 is a cross-sectional view of a support member 3 showing an example of such a shape. The example of Fig. 14 shows an example in which toothed portions 33a and 33b are formed in the bridge portion 33 at the stage of the primary molded product 40 (S2 in Fig. 11 ).

[0071] The tooth impression portion 33a is formed on one surface in the Z direction and forms a tooth impression of the subject together with the tooth impression portion 34 formed of elastomer 41 (S3 in FIG. 11). The tooth impression portion 33a mainly forms a tooth impression of the occlusal surface of the subject's teeth, and the tooth impression portion 34 mainly forms a tooth impression so as to encase the subject's teeth.

[0072] Similarly, the tooth impression portion 33b is formed on the other surface in the Z direction, and forms a tooth impression of the subject together with the tooth impression portion 35 formed of elastomer 41 (S3 in FIG. 11 ). The tooth impression portion 33b mainly forms a tooth impression of the occlusal surfaces of the subject's teeth, and the tooth impression portion 35 mainly forms a tooth impression so as to encase the subject's teeth. In the illustrated example, the outer surface of the tooth impression portion 35 (the side facing the coil support portion 31) extends linearly from the bridge portion 33.

[0073] The formation of the tooth-shaped portions 33a and 33b allows the subject to bite more deeply into the bridge portion 33, stabilizing the position of the receive coil device 1. In addition, the subject's mouth opening is reduced, reducing discomfort felt by the subject during the examination.

[0074] The toothed portions 33a and 33b can be formed by using the toothed dies 5a and 5b in step S2 of the manufacturing method illustrated in Fig. 11, or by having the subject actually bite the primary molded product 40. Only one of the toothed portions 33a and 33b may be formed.

[0075] In the example of Fig. 14, one of the pair of coil support parts 31 has an extension part 310 formed to fit the shape of the interior of the oral cavity of the subject. In this way, the size, length, and shape of the coil support part 31 can be adjusted to fit the shape of the interior of the oral cavity of the subject, and the adjustment work can be performed in S2 of the example of Fig. 11. In the example of Fig. 14, only one coil support part 31 has the extension part 310, but the other coil support part 31 may also have a part equivalent to the extension part 310.

[0076] Although the embodiments of the invention have been described above, the invention is not limited to the above-described embodiments, and various modifications and changes are possible within the scope of the gist of the invention.

Claims

1. A receive coil device (1) for receiving magnetic resonance signals generated from a subject (200), comprising: a first loop coil element (C1) corresponding to a first channel (CH1); and a second loop coil element (C2) corresponding to a second channel (CH2), wherein the first loop coil element (C1) is arranged outside the dentition (202) in the oral cavity of the subject (200) so that its loop surface (CF) faces the area to be examined, and the second loop coil element (C2) is arranged inside the dentition (202) in the oral cavity of the subject (200) so that its loop surface (CF) faces the area to be examined.

2. A receive coil device (1) according to claim 1, comprising: a third loop coil element (C3) corresponding to a third channel (CH3); and a fourth loop coil element (C4) corresponding to a fourth channel (CH4), wherein the third loop coil element (C3) is arranged outside the row of teeth (202) in the oral cavity of the subject so that its loop surface (CF) faces the region to be examined; and the fourth loop coil element (C4) is arranged inside the row of teeth (202) in the oral cavity of the subject so that its loop surface (CF) faces the region to be examined; the first loop coil element (C1) and the third loop coil element (C3) are arranged so as to be offset in the direction of the row of teeth (D1); and the second loop coil element (C2) and the fourth loop coil element (C4) are arranged so as to be offset in the direction of the row of teeth (D1).

3. A receive coil device (1) according to claim 2, characterized in that the first loop coil element (C1) and the third loop coil element (C3) are arranged offset in the tooth row direction (D1) so as to partially overlap each other, and the second loop coil element (C2) and the fourth loop coil element (C4) are arranged offset in the tooth row direction (D1) so as to partially overlap each other.

4. A receive coil device (1) according to claim 1, comprising a support member (3) that supports the first loop coil element (C1) and the second loop coil element (C2) in the oral cavity of a subject (200), the support member (3) including: a first coil support part (31) that supports the first loop coil element (C1) outside the dentition (202) in the oral cavity of the subject (200); a second coil support part (31) that supports the second loop coil element (C2) inside the dentition (202) in the oral cavity of the subject (200); and a base part (32) that is provided between the first coil support part (31) and the second coil support part (31) and is sandwiched between the upper and lower teeth of the subject.

5. The receive coil device (1) according to claim 4, wherein the base portion (32) has upper and lower dental impressions (34, 35) of the subject formed thereon.

6. A receive coil device (1) according to claim 1, characterized in that the first loop coil element (C1) and the second loop coil element (C2) have a rectangular shape that is short in the tooth row direction (D1) and long in the tooth up-down direction (D2).

7. A receiving coil device (1) for receiving magnetic resonance signals generated from a subject (200), comprising: a first head unit (10) including a first loop coil element (C1) corresponding to a first channel (CH1) and a first covering portion (15a) covering the first loop coil element (C1); a second head unit (10) including a second loop coil element (C2) corresponding to a second channel (CH2) and a second covering portion (15a) covering the second loop coil element (C2); and a support member (3) for supporting the first head unit (10) and the second head unit (10) in the oral cavity of the subject, wherein the support member (3) a first coil support part (31) to which the first head unit (10) is detachably attached outside the dentition (202) in the oral cavity of the subject so that the loop surface (CF) of the first loop coil element (C1) faces the region to be examined; a second coil support part (31) to which the second head unit (10) is detachably attached inside the dentition (202) in the oral cavity of the subject so that the loop surface (CF) of the second loop coil element (C2) faces the region to be examined; and a base part (32) provided between the first coil support part (31) and the second coil support part (31) and held between the upper and lower teeth of the subject.

8. A receive coil device (1) according to claim 7, wherein the first head unit (10) is covered by the first covering portion (15a) and includes a third loop coil element (C3) corresponding to a third channel (CH3); the second head unit (10) is covered by the second covering portion (15a) and includes a fourth loop coil element (C4) corresponding to a fourth channel (CH4); in the first head unit (10), the third loop coil element (C3) is arranged so that its loop surface (CF) faces the region to be examined and is shifted in the tooth row direction (D1) from the first loop coil element (C1); and in the second head unit (10), the fourth loop coil element (C4) is arranged so that its loop surface (CF) faces the region to be examined and is shifted in the tooth row direction (D1) from the second loop coil element (C2).

9. A receive coil device (1) according to claim 7, characterized in that the first coil support portion (31) forms a first slot (37) into which the first head unit (10) is inserted, and the second coil support portion (31) forms a second slot (37) into which the second head unit (10) is inserted.

10. A receive coil device (1) according to claim 7, characterized in that the first head unit (10) and the second head unit (10) each include a first engagement portion (16), and the first coil support portion (31) and the second coil support portion (31) each include a second engagement portion (36) that engages with the first engagement portion (16).

11. A receive coil device (1) according to claim 10, characterized in that the first engaging portion (16) of the first head unit (10) is formed by the first covering portion (15a), and the first engaging portion (16) of the second head unit (10) is formed by the second covering portion (15a).

12. A receive coil device (1) as set forth in claim 10, characterized in that the first head unit (10) is positioned in the tooth row direction (D1) and the tooth up-down direction (D2) by the engagement between the first engagement portion (16) of the first head unit (10) and the second engagement portion (36) of the first coil support portion (31), and the second head unit (10) is positioned in the tooth row direction (D1) and the tooth up-down direction (D2) by the engagement between the second engagement portion (16) of the second head unit (10) and the second engagement portion (36) of the second coil support portion (31).

13. A receive coil device (1) according to claim 7, characterized in that the support member (3), the first covering portion (15a) and the second covering portion (15a) are made of biocompatible silicone.

14. A receiving coil unit (2A) for receiving magnetic resonance signals generated from a subject (200), comprising: a plate-shaped head unit (10) placed on the side of the subject's dentition (202); and a cable (20) extending from the head unit (10), wherein the head unit (10) includes at least one loop coil element (C1); and a coil covering portion (15a) that covers the at least one loop coil element (C1) and forms the outer shape of the head unit.

15. A receiving coil unit (2A) according to claim 14, characterized in that the head unit (10) includes a plurality of loop coil elements (C1, C3) corresponding to a plurality of channels (CH1, CH3).

16. A receiving coil unit (2A) according to claim 14, characterized in that it comprises a cable covering part (15b) formed integrally with the coil covering part (15a) and covering a part of the cable (20).

17. A receiving coil unit (2A) according to claim 14, characterized in that the outer shape of the head unit (10) is a rectangle with rounded corners.

18. A receiving coil unit (2A) according to claim 14, characterized in that the head unit (10) is supported by a support member (3) attached to the teeth of the subject (200), and the coil covering portion (15a) includes an engaging portion (16) that engages with the support member (3).

19. A manufacturing method for manufacturing a component (3) constituting a receive coil device (1) that receives magnetic resonance signals generated from a subject (200), wherein the receive coil device (1) comprises: a first head unit (10) including a first loop coil element (C1) corresponding to a first channel (CH1) and a first covering portion (15a) that covers the first loop coil element (C1); a second head unit (10) including a second loop coil element (C2) corresponding to a second channel (CH2) and a second covering portion (15a) that covers the second loop coil element (C2); and a support member (3) as the component that supports the first head unit (10) and the second head unit (10) in the oral cavity of the subject, wherein the support member (3) comprises: a first coil support part (31) to which the first head unit (10) is detachably attached outside the row of teeth (202) in the oral cavity of the subject so that the loop surface (CF) of the first loop coil element (C1) faces the region to be examined; a second coil support part (31) to which the second head unit (10) is detachably attached inside the row of teeth (202) in the oral cavity of the subject so that the loop surface (CF) of the second loop coil element (C2) faces the region to be examined; and a base part (32) provided between the first coil support part (31) and the second coil support part (31) and held between the upper and lower teeth of the subject, wherein the manufacturing method includes: a step (S1) of creating dental impressions (5a, 5b) of the subject; a step of using the toothed dies (5a, 5b) to create a primary molded product (40) having the first coil support portion (31) and the second coil support portion (31); and a step of attaching an uncured curing material (41) that constitutes the base portion (32) to the primary molded product (40) and curing the uncured curing material, thereby forming the base portion (32).

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